Not as well behaved as Baystate Blue, not as bright as other vibrant pinks. Bleedthrough problems, bleedout problems, and holy feathering, Batman! Skip this one—there are much better bright pinks out there.

There are rumors that Diamine makes all of Akkerman’s inks, and debate within those rumors as to whether they are simply re-branded or slightly altered version of Diamine inks. Either way, this ink is very nice.

This is an ink with one crazy long name, but luckily it’s good enough to justify it. There’s some serious discussion about whether or not Akkerman inks are simply re-bottled Diamine inks. I haven’t seen anything to convince be either way, but I will say that this ink is VERY similar to its supposed analog, Diamine Prussian Blue (which, coincidentally, I also love).

The clear winners are Upper Ganges Blue, Baystate Blue, Bad Blue Heron, 54th Massachusetts, and Legal Lapis. It’s no coincidence that Baystate Blue and Bad Blue Heron are two of my favorite inks ever, and 54th is making its way up that list too.

This has become one of my favorite dark blue inks. Sei-Boku, along with its dark black sibling, Kiwa-Guro, is a fountain pen-safe pigmented ink. The vast majority of fountain pen inks derive their beautiful hues from dyes rather than pigments, as pigments tend to clog the small channels of fountain pen feeds. And while I’m unsure of if this ink gets its color from only pigment or a mix of pigment and dyes (I’m guess the latter), I can attest that this ink ran through the test pens perfectly fine and without any trouble. And while the manufacturer recommends flushing your pen between fills of this ink, that’s a pretty good ink hygiene habit to get into anyways.

On the page this ink also has a very prominent red/pink sheen, which I’ve found is a common color of sheen for blue inks.

And the one big plus for me with this ink? Here’s what it looks like on cheapo copy paper:

Look at that shading! The best part? It retains its fantastic sheen on copy paper as well! There is only one other ink I can think of that don’t feather and shade heavily and retain sheen: J. Herbin Rouge Hematite 1670. But as for blue inks that share this great behavior? In my experience, only Noodler’s Bad Blue Heron and Rohrer and Klingner’s Salix (an iron gall ink).